Generally, the overall structure of a pedestal pump is that the impeller pump body is submerged in water, the motor is above the water surface, the motor shaft and impeller needs to be connected by a long shaft and a coupling to achieve transmission thereof. The traditional driving shaft is a solid metal shaft or a hollow alloy plastic pipe, the longer the shaft is, the worse the machining accuracy will be, and the higher the cost will be, especially when the alloy plastic shaft is used for a period time, deformation will occur and friction will happen on the outer tube, this causes noise or failure in the operation of the pump.